Various adjustment mechanisms for a motor vehicle seat are known from the prior art. The extent and the differentiation of the seat adjustment are substantially dependent on the level of comfort and equipment of the motor vehicle. Customarily, the position of the two front motor vehicle seats can be displaced forward and rearward on what are referred to as seat rails, in order to enable individuals of different heights to readily operate the gas, brake and optionally clutch pedals. This is generally referred to as a linear seat adjustment or two-way adjustment. In most cases, the inclination of a backrest of the motor vehicle seat can also be adjusted. In the case of comfortably equipped motor vehicle seats, the adjustment mechanism additionally permits, for example, adjustment of the height and of the seat inclination of the motor vehicle seat. What is referred to as a six-way seat adjustment therefore includes the adjustability of the seat in the horizontal and vertical directions and also the adjustment of the inclination of the backrest. The adjustment of the motor vehicle seat can be carried out here, for example, with the aid of lateral hand wheels, levers with a pumping movement or via switches with electrical or electro-hydraulic support.
The adjustment mechanism typically has rockers which are mounted in an articulated manner and are operable by motor or else manually. In a known manner, for example, a front rocker and a rear rocker are provided in each case on the left and right sides of the vehicle seat, said rockers being connected in each case by means of pivot points to the seat/the seat trough and also to a rail, which is mounted displaceably in the longitudinal direction of the motor vehicle on a vehicle floor.
In the event of an impact of the motor vehicle against an obstacle or the like, an occupant on the motor vehicle seat is very severely accelerated relative to the motor vehicle seat. This may result in injuries to the vehicle occupant. In addition, the high acceleration forces cause high torques at the pivot points of the rockers. This, in turn, can lead to an overloading of the vehicle seat, in which individual components of the adjustment mechanism (for example the rockers) are destroyed or severed.
DE 10 2007 039 862 A1, which is incorporated by reference herein, discloses a seat height adjustment device for a motor vehicle seat, in which a seat support is connected to a longitudinal adjustment rail by means of a front and a rear pivoting support. Each pivoting support is coupled rotatably to the longitudinal adjustment rail via a first coupling point and to the seat support via a second coupling point. Each pivoting support here comprises a subregion with a width which is reduced transversely with respect to a longitudinal axis of the pivoting support and is arranged between the respective coupling points. In the event of an impact of the motor vehicle, the pivoting supports are deformed or buckled in relation to the longitudinal axis in the predetermined weakened subregion as a consequence of the actions of force.
However, the structure of the motor vehicle seat is weakened in general by this measure. Age-induced material fatigue can therefore also result in a deformation of the pivoting supports and therefore in a functional impediment of the adjustment mechanism. Furthermore, there is the risk of the pivoting supports being severed in the event of a vehicle impact and therefore of a higher risk of injury for the vehicle occupants arising.
Against this background, it would be beneficial to specify an improved adjustment mechanism for a motor vehicle seat, said adjustment mechanism avoiding the above disadvantages.